This project seeks to investigate the use of C11-labeled compounds in diagnostic nuclear medicine. Having identified various agents as potential C11-labeled radiopharmaceuticals for the detection of cancer and imaging of various organs, methods are devised to synthesize and purify such agents. Following preclinical tests of these materials in animals, they will then be tested in human subjects. Using C14 as a label for C11 we have devised rapid synthesis and purification techniques (less than 1 hr) for the preparation of C11- labeled 1-aminocyclopentane-carboxylic acid (ACPC), a cancer detection agent, and DL-tryptophan, a pancreas imaging agent. Clinically useful C11-labeled preparations oof these two agents are expected to be made available in the coming year using the Oak Ridge National Laboratory's 86-inch proton cyclotron. After preliminary studies in animals, we will test the clinical efficacy of C11-labeled ACPC and DL-tryptophan for the visualization of tumor and pancreas. In further developmental studies we will attempt to devise methods for the synthesis of C11-labeled estradiol (tumor and pancreas) and thymidine (tumor). We will also carry out preliminary tests in animals of various alpha substituted amino acids (analogous to ACPC) as possible tumor-localizing agents.